1. Field of the Invention
This invention relates generally to method for fault detecting in electric components located in vehicle circuits and, more particularly, to a tester device and testing method for testing the electrical operating characteristics of an electric fuel pump.
2. Related Art
When a vehicle's fuel system is malfunctioning, the electric fuel pump is often considered first to determine whether it is defective. A common issue encountered when attempting to diagnose a problem with a vehicle's fuel system is that the technician is unable to quickly yet thoroughly test the electric fuel pump so as to either identify it as the problem or to rule it out. According to most prior art techniques, a technician would test the voltage at the fuel pump electrical connection on the vehicle wire harness. In some cases, this was accompanied by the laborious process of uninstalling the fuel pump from the vehicle. If the voltage at the electrical connection measured within an acceptable range of the standard operating voltage of the electrical fuel pump (commonly 12 VDC), the technician would conclude that the electrical system of the vehicle was operating properly and, that the fuel pump was defective. This conclusion commonly dictated replacing the fuel pump, and possibly returning the original fuel pump to its manufacturer seeking reimbursement as a defect.
This approach often lead to an erroneous conclusion concerning the operability of the fuel pump. For example, if the fuel pump wire harness was defective, the simple voltage test might still register 12 VDC when in an unloaded state. In many reported cases, technicians using this simple voltage test have mistakenly replaced the fuel pump in a vehicle multiple times without realizing that the fuel pumps were never defective but instead the electrical system of the vehicle was the root cause of the problem. In each of these instances, substantial additional cost and inconvenience is caused to the vehicle owner, pump manufacturer and/or service technician due to the misdiagnosis.
A more recent prior art system and method for in situ testing the electrical operation of an electric fuel pump is shown in U.S. Pat. No. 7,710,121 to Harvey et al., issued May 4, 2010 and assigned to the assignee of the present invention. The entire disclosure of U.S. Pat. No. 7,710,121 is hereby incorporated by reference and relied upon. The system and method described in U.S. Pat. No. 7,710,121 represents a significant advancement over earlier systems and methods, and has enjoyed rapid and widespread acceptance in the marketplace. There exists however, a continuous desire for further improvement to provide even more easy to use, more efficient systems and methods for field testing the electrical operation of an electric fuel pump.